Chapter 1 (METHODS) - Histoworld Flashcards

1
Q

When using a compound microscope, objective lenses can be found to have a magnification of all of the following, EXCEPT?

A

1000x

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2
Q

What is “compound microscope”?

A

Microscope with two lenses

  • A compound microscope has two lenses: an eyepiece lens and objective lens. The eyepiece lens usually has a magnification of 10X. There are objective lenses on the revolving nosepiece with varying magnifications. Most compound microscopes have objective lenses with magnification of 4X, 10X, and 40X. Some compound microscopes also have an oil immersion lens with a magnification of 100X.
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3
Q

What is the total magnification achieved with a compound microscope?

A

d. Magnification of ocular lens multiplied by the magnification of the objective lens
* To calculate the total magnification achieved with a compound microscope, the magnification of the ocular lens is multiplied by the magnification of the objective lens. For example, if viewing a sample with the 40x objective, the total magnification would be calculated as follows: a 10X ocular lens used with a 40X objective lens, the total magnification is 400X (10 x 40).

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4
Q

What is the maximum resolving power seen with a compound microscope?

A
  1. 2 micrometers
    * Resolving power is the ability to see two things as discrete images. With normal vision, there is a resolving power of about of 100 micrometers. A compound microscope has a resolving power of approximately .2 micrometers. In other words, two marks .2 micrometers apart can be seen as two distinct entities. Any closer than this, they are perceived as one object.
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5
Q

What is the turret?

A

Nosepiece

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6
Q

On a microscope, what structure connects the eyepiece to the objective lens?

A

Tube

  • The base is the bottom of the microscope. The revolving nosepiece is also called a turret. The objective lens is attached to the nosepiece (or turret). The slide rests on the stage. The tube is the structure which connects the eyepiece to the objective lenses (it is shaped like a tube; thus, its name). The diaphragm controls the diameter of the cone of light.
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7
Q

In a good compound microscope, the focus knob does not have to be readjusted when changing the magnification. What is this phenomenon called?

A

Parfocal

  • Parafocal is the term used for a microscope if the focus knob does not have to be readjusted when changing the magnifications. This phenomenon is seen with good compound microscopes. In other words, when the specimen is in focus at 4X and the objective is switched to 10X, the specimen remains in focus.
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8
Q

What is another name for the light microscope?

A

Compound microscope

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9
Q

Which microscope does not rely on visible light?

A

Transmission electron microscope

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10
Q

Which microscope makes things appear three dimensional?

A

Dissection microscope

  • A simple microscope has only one lens. A compound microscope utilizes two lenses: an ocular lens and an objective lens. The compound microscope is also referred to as a “light microscope” or “bright field microscope”. A phase contrast microscope is useful for examining living cells, because the specimen does not need to be stained. A dissection microscope uses low power magnification. Things appear three dimensional with a dissection microscope. A transmission electron microscope does not use light, but rather a beam of electrons.
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11
Q

When using a compound microscope, what is the magnification of the oil immersion lens?

A

100x

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12
Q

What is the usual magnification of the ocular lens on a compound microscope?

A

10x

  • The usual magnification of an ocular lens on a compound microscope is 10X. Some microscopes have a 15X eyepiece lens. The ocular lens is the lens at the top of the tube, the one that you first look through when using a microscope. It is also called the eyepiece lens.
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13
Q

When using oil immersion to view a tissue, what is the refractive index of the oil?

A

Same as glass

  • With light microscopy, there normally is a space of air between the slide and the lens. Oil immersion replaces that space of air with oil. The refractive index of the oil is the same as glass.
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14
Q

What is the role of the condenser lens?

A

Focus the light on the specimen

  • The role of the condenser lens is to focus light on the specimen. It is used with higher magnifications.
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15
Q

On a microscope, what structure varies the diameter of the cone of light?

A

Diaphragm

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16
Q

Where do you place the slide when using a microscope?

A

Stage

17
Q

What is the bottom of a microscope called?

A

Base

18
Q

What is another name for the bright field microscope?

A

Compound microscope

19
Q

Which microscope would be particularly useful for looking at living cells?

A

Phase contrast microscope

20
Q

Which type of microscope has only one lens?

A

Simple microscope

21
Q

Which of the following stain blue with H&E stain?

A

Nucleus

  • “H&E” stands for hematoxylin and eosin. Hematoxylin can be thought of as a basic dye. It binds to acidic structures, staining them blue to purple. For example, it will bind and stain nucleic acids. Therefore, the nucleus stains blue.
22
Q

What are Sudan stains used primarily for?

A

Fat

  • Sudan stains are used for staining of lipids and phospholipids. Examples of such stains are sudan black and sudan IV. Oil red O is another stain used for demonstrating fat.
23
Q

What is Mucicarmine stain used primarily for?

A

Epithelial mucin

  • Mucicarmine is used to see epithelial mucin. It stains it a deep red.
24
Q

What is Wright’s stain used primarily for?

A

Blood

  • Wright’s stain is used for blood smears and bone marrow. Red blood cells will stain pink.
25
Q

What color do elastic fibers stain with Verhoeff Elastic stain?

A

Blue/black

  • Verhoeff Elastic stain stains elastic fibers blue/black. Collagen stains pink/red.
26
Q

During the preparation of a routine H&E slide, what step occurs after the tissue is preserved?

A

Dehydration

27
Q

During the preparation of a routine H&E slide, how is the tissue preserved?

A

Fixation

28
Q

During the preparation of a routine H&E slide, what allows the tissue to be visualized?

A

Staining

29
Q

Which of the following would be best suited to visualize reticular fibers?

A

Silver impregnation

30
Q

Which of the following would be best suited to visualize lipid?

A

Sudan stain

31
Q

During the preparation of a routine H&E slide, what allows the tissue to hold its form?

A

Embedding in paraffin

32
Q

During the preparation of a routine H&E slide, what step occurs after the tissue is embedded in paraffin?

A

Slicing

33
Q

During the preparation of a routine H&E slide, what step occurs after the tissue is stained?

A

Dehydration

  • There are several steps in the preparation of a slide for microscopic examination. First, the tissue is “fixed” with formalin. This preserves it. After the tissue is fixed, it is dehydrated (dehydration will occur twice during slide preparation). The tissue sample is then embedded in paraffin. This forms a solid block, so that it can be placed in a microtome. It is then thinly sliced using a microtome. A thin slice of the specimen is then placed on a slide. The paraffin is removed by dissolving it with a chemical. The tissue is then rehydrated. In order to view the tissue, it is stained. After it is stained, it is again dehydrated. A coverslip is then mounted on top of it. The specimen is then ready for viewing.
34
Q

Which of the following is an acid dye?

A

Eosin

  • Eosin is an acid dye. It will bind to and stain basic structures (or negatively charged structures), such as cationic amino groups on proteins. It stains them pink. Cytoplasm, muscle, connective tissue, and decalcified bone matrix all stain pink with eosin. “H&E” stand for hematoxylin and eosin. Hematoxylin and eosin stain is used for routine tissue preparation frequently.
    Azure II, Toluidine blue, Methylene blue, Thionine are all basic dyes.
35
Q

Which of the following would be best suited for peripheral blood smears?

A

Wright’s stain

36
Q

Which of the following stains is used for routine histological examination?

A

Hematoxylin and eosin stain

37
Q

What is Prussian blue stain used for?

A

Iron

  • Prussian blue stain is used to stain iron.
38
Q

What color does hematoxylin stain structures?

A

Blue

  • “H & E” stands for hematoxylin and eosin. Hematoxylin can be thought of as a basic dye. It binds to acidic structures, staining them blue to purple. For example, it will bind and stains nucleic acids. Therefore, the nucleus stains blue.
39
Q

Which of the following would be best suited to differentiate collagen fibers from other fibers?

A

Masson’s trichrome stain

  • A peripheral blood smear would be best visualized with Wright’s stain. Hematoxylin and eosin stain is the most commonly used tissue stain for routine histological examination. Lipids are best displayed with a sudan stain. Silver impregnation, such as with a reticular stain, can be used to visualize reticular fibers. Collagen fibers can be differentiated from other fibers by staining with Masson’s trichrome stain.